pytopo: Topographic Maps for Linux

PyTopo is a Python-gtk script which interprets
local tiled map data (for instance, from a Topo! data CD),
and displays it in an interactive viewer, where you can scroll
to adjacent maps, switch between resolutions, or produce a map
image for printing or editing.

Why does PyTopo exist?
There were several existing Linux mapping applications which take data
from online web sites or roads databases, and others which take GPS
data and correlate it with online maps.
But I typically need maps when I'm travelling and don't have
net access!
I couldn't find any apps that would display data for any location,
without requiring a GPS, using local map sources with no net connection
needed.
(There are a few possibilities but nothing that really solves the problem:
GPSdrive claims it can do local mapping now,
but I've tried three versions with no luck getting it to run at all.
And there's a neat little
program called TangoGPS that can download and show OSM maps, but it has a
difficult interface that's optimized for cellphones.)

1.0 got all kinds of cool new stuff, including map dragging, more user
interface for zooming and saving sites, track logs saved in ~/Tracks,
etc. so it's usable without a keyboard, e.g. on a tablet.
Embarassingly, we were so intent on adding new features that
we never got around to making a formal release! So 1.1 has all
those features, plus a lot of reliability enhancements to make
everything work more solidly.

The big news in 0.9 is the new OSM Map Collection, which can download map
tiles from the OpenStreetMap project.
(Aside: this is a great project, so if you're interested in mapping, join
up and help add to the public map!) You no longer need your own big set
of map data; just set up an OSM Map Collection with appropriate download
URL, point at a longitude/latitude and specify the zoom level, and pytopo
will download the tiles you need. These are cached forever (unless you delete
them yourself), so once you've downloaded an area you're good to go offline
and your maps will still work.

There's an experimental MeeGo package for
anyone interested in trying it, and I'd be interested to know if it
works on other RPM platforms as well:
PyTopo-1.0-1-beta1.noarch.rpm.

Using PyTopo

The first time you run pytopo, it will create a configuration file,
typically ~/.config/pytopo/pytopo.sites (if it can't create that
it will fall back to ~/.pytopo instead).

You might want to take a look at the file: this is where you can add
additional map collections or sites you visit frequently.
By default, pytopo will download OpenStreetMap tiles to ~/Maps.
Of course, you can change that.
See the PyTopo File Formats page
for more details.

pytopo -p will print out a list of known sites.
With the initial default configuration you'll just have a few cities like
san-francisco, new-york, london, sydney;
this is mostly to show you how to add your own points of interest.

Key bindings

Left, Right,Up, Down

Scroll the map in the indicated direction.

+/=, -

Zoom in to the 7.5 minute series, or out to the 15 minute series.
(Zooming isn't supported in other map formats yet.)

s

Save the current map to a file under $HOME/Topo

Space

Print (to standard output) the current coordinates of map center.

Clicking in the map displays the coordinates of where you
clicked, as well as the distance and bearing from the last clicked
point.

Note that dragging in the map doesn't move the map.
You need to use arrow keys to move around.
I do plan to implement dragging at some point, and I don't think
it's that hard; I've just been more concerned about getting the OSM
collections working first.

Preloaded Map Data

Aside from OpenStreetMap data, pytopo can use local map data
on disk or CD.

The Topo! local area and specific park map packages
sold in camping/hiking stores
(sometimes under the aegis of National Geographic) are
reasonably priced as a source of map data.
They come with Windows software, but Linux users can ignore
the software and use the data files, which are
standard GIF, named in a fairly straightforward way.
They're a good source of US map data.

Making Your Own Map Collections

You can buy map bits directly from the USGS, but they have
a hefty setup fee so it's not cost effective unless you're buying
quite a lot.

For some areas, you can download topo maps; for instance,
for California you can get maps in TIFF format from the
California
Spatial Information Library. You still have to split up the
maps into maplets, though; if you have ImageMagick, you can use
a command like

Note: previously I included -trim as part of that line, and
a lot of pages you'll find googling for image splitting will tell you
to use -trim. Don't: it will give you maps of inconsistent sizes,
and pytopo has no way to tell where the origin of the map should be.

A map split this way can be read with PyTopo 0.5 or later.
Maps downloaded as PDF (such as USGS geologic maps) might work
in imagemagick, but if not, try converting them
to a raster format before splitting, using a program like GIMP
or a command like

gs -sDEVICE=jpeg -r300 -sOutputFile=output-map.jpg input-map.pdf

Non-interactive mapping scripts

I wrote some older commandline helper scripts, but honestly, I don't use them
myself and don't vouch for them. I list them here merely on the chance
that someone might find one of them a useful building block:

topomap, which takes start and end coordinates
and builds a custom map. This is mostly replaced by the 's'
functionality in pytopo, but might be useful if you need to display
a map larger than you can display on your screen.

onetopo, which takes start coordinates and
combines the maplets into one complete USGS 7.5-minute map.

Is it Only For Linux?

PyTopo should run fine on any system which has Python, gtk,
gdk-pixbuf, and PyGTK. I've tried to make the code as portable as
I can, but I've only tested it on Linux.
If it doesn't work for you, please let me know.

Coming Soon

(Stuff I want that should be easy to implement or is already
in progress.)

Navigating by dragging with the mouse, like people expect these days,
rather than moving only with arrow keys by multiples of a whole maplet.

Zoom farther out or in (i.e. scale the map images rather
than always displaying them at 1:1).

Bugs / Wishlist

(Stuff that would be nifty, but is either difficult,
or requires additional map data that I'd have to pay for.
If you want something on this list, bribing me with interesting
map data would be an excellent approach.)

Track logs don't always line up exactly with Topo! map collections;
I think the Topo! maps may use a different "datum" (coordinate system)
from the WGS 84 that most GPS devices use. They should line up with
OSM map collections.

Draw maps from non-tiled openstreetmap vector data.

Combine with elevation data to make pretty maps.
(The limiting factor here is finding an open source of elevation data
that pytopo can read easily.)

Flip back and forth between two sets of maps of the same area,
e.g. road map/topographic map/geologic map.
(Limiting factor: getting enough useful map data, preferably geologic,
to make it worth putting in the work.)

Better control over projections and datum -- PyTopo isn't smart
about those at all.

Change Log

1.1, November 16 2011

Fix a lot of minor bugs and some usability problems with features
introduced in 1.0.

1.0, May 7 2011

Lots of UI additions to make pytopo work well on MeeGo and other
tablets. Now there's a "pin", you can save sites, go to saved track
logs and lots of other goodies, including some great contributions
from Ville Jyrkkä.

0.9, October 30, 2010

New format! OSMMapCollection handles OpenStreetMap tiles, including
(optionally) downloading them for you.
Figure out trackpoint files from context -- no need to use -t any more.
So now you can run pytopo *.gpx site
If there's no config file initially, create a default one using tiles
from the default OSM website and a few major cities.
More flexible handling of initial window width.

0.8, June 20, 2009

Support track/waypoint files;
support worldwide coordinates by using negative longitudes when
west of the prime meridian;
complete codebase refactor -- cleaner, more generalizable, more OO code;
base class for implementing new tiled map collections;
some associated MapCollection file format changes;
accept config file in .config/pytopo as well as ~/.pytopo;
introduce new (still buggy and undocumented) OSMMapCollection.

0.7, September 10, 2008

Add -c to find the center of a collection;
fix a bug when latitude or longitude is less than 10°.